[1] According to German Seligman, Merchants of Art: 1880-1960, Eighty Years of Professional Collecting, New York, 1961, p. 13, it was Sigismond Bardac who sold the busts to his father, Jacques Seligmann. . However, according to René Gimpel, Diary of an Art Dealer, New York, 1966, p.7-8, it was Joseph Bardac, Sigismond's brother, who owned both the marbles of the Brongniart children and the terracottas; Gimpel sold the terracottas to Widener.

[2] See notes of Charles Seymour, Jr., about busts by Houdon in the NGA collection, and the letter of 17 January 1911 from Joseph Bardac to Jacques Seligmann, in NGA curatorial files.